Income Taxes - Components of Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Apr. 28, 2018	Apr. 29, 2017
Deferred tax assets:
Capital accumulation plan	$ 4,862	$ 7,676
Inventory related items	4,407	6,236
Bad debt allowance	1,052	2,317
Stock based compensation expense	6,514	8,663
Interest rate swap	4,712	8,656
Foreign tax credit	8,472	8,917
Other	11,748	14,269
Gross deferred tax assets	41,767	56,734
Less: Valuation allowance	(13,830)	(14,053)
Total net deferred tax assets	27,937	42,681
Deferred tax liabilities
LIFO reserve	(19,727)	(25,833)
Amortizable intangibles	(84,778)	(133,037)
Goodwill	(41,635)	(61,108)
Property, plant, equipment	(33,376)	(14,389)
Total deferred tax liabilities	(179,516)	(234,367)
Deferred net long-term income tax liability	$ (151,579)	$ (191,686)